Gerald Andrejcak, a reptile expert and assistant director at the animal welfare group Common Sense for Animals, says he saw the snake in a boathouse last week and that he identified it as an anaconda by its head and coloration pattern.

The New Jersey Department of Environmental Protection, however, has not confirmed the presence of an anaconda in the lake.

“With thousands of eyes, cell phones, iPhones and iPads, if there is such a creature in the water, you’d think at some point someone would get a picture or see something,” said Larry Ragonese, a DEP spokesman. “It’s getting to be kind of a Loch Ness monster kind of story.”

Local beachgoers were not concerned by the reports of a deadly snake in the lake. Among the swimmers and sun tanners were a group of 70 parents and children from Weehawken in Hudson County and a group of 40 campers from a local YMCA.

“We brought two busloads of people and they went right into the water,” said Pat Mazure, a supervisor for the Weehawken trip.

As Mazure was talking about trip attendees’ lack of concern for the snake, her daughter called to let her know there were reports of an anaconda in the lake.

“She told me not to go in the water,” Mazure said.

Kristen Lewis and her 9-year-old twin daughters, from Mine Hill in Morris County, weren’t worried about the snake either.

“I figured it wouldn’t be in this area anyway,” Lewis said. “I had the week off so I was coming out and doing something.”

Still, some beachgoers were happy to come to the lake but stayed out of the water.

“Why would someone make that up?” said Silvia Chavez, from Weehawken, who was staying far from the shore.

If there is an anaconda in the lake, Ragonese and Andrejcak agree that it most likely came from a pet owner who did not want it anymore and dumped it in the lake.

The DEP has worked with state police, marine police and its own experts to look for the snake, but has yet to find anything conclusive. Local animal control bureaus have also set up traps for the snake.

Meanwhile, Andrejcak has been looking for the anaconda on his own. The snake slid through his legs in the boathouse, he said, but he was not able to grab it and has continued to help with the search.

“Even with my eyewitness account, five or six eyewitnesses, but no pictures, they’re saying there should be pictures,” Andrejcak said of the DEP. “Until they get physical evidence they’re not doing a thing.”

“We don’t want to needlessly alarm people,” Ragonese said. “It’s summer, and people use the lake.”